// 数据域
// 左侧的子节点
// 右侧的子节点

function TreeNode(val) {
    this.val = val;
    this.left = this.right = null;
}

const node1 = new TreeNode(1);
const node2 = new TreeNode(2);
const node3 = new TreeNode(3);

node1.left = node2;
node1.right = node3;


const obj = {
    val: 1,
    left: {
        val: 2,
        left: null,
        right: null
    },
    right: {
        val: 3,
        left: null,
        right: null
    }
}

